Farming began in the West roughly 10,000 years ago, with Neolithic villagers slowly domesticating grains in the regions that today we call Turkey, Syria, and Iraq. Just a few thousand years later, it had spread throughout Europe. But how did it get there, and who brought it? A new study of ancient DNA from Irish settlers between 5,000 and 3,000 years ago helps to tell this story.
Trinity College geneticist Lara Cassidy and her colleagues describe their work in an article out today from Proceedings of the National Academy of Science. They sequenced the genomes of four ancient Irish people: a Neolithic woman who was buried in a megalithic tunnel grave about 5,000 years ago in Ballynahatty (see video below for what a megalithic grave looks like) and three Bronze Age men discovered in an underground "cist" grave on Rathlin Island from about 4,000 years ago.
The differences between the Ballynahatty woman and the Rathlin men are dramatic—during the millennium that separated their lives, it's likely that Irish people and culture underwent a major upheaval. The Ballynahatty woman likely had dark hair and eyes, with distant kin from the Near East, where western agriculture was born. She also shared genetic similarities with people from the region now known as Spain, which suggests that her ancestors took a southerly route along the coast as they migrated from the Near East to Ireland. The Neolithic peoples of Spain also buried their dead in megalithic tunnel graves, which suggests a cultural continuity between the Ballynahatty woman's people and her ancestors.